Rest Serializer isPrimaryType should not use store.modelFor

[igorT]

Currently Rest Serializer implicitly does type normalization in store.isPrimaryType by calling store.modelFor. It shouldn't do that, it should normalize the type name itself

[runspired]

TL;DR

isPrimaryType is used in one location to check if the result of store.modelFor(modelName) is equal to the ModelClass provided to the serializer as the primary ModelClass.

It would be better to check if normalizeModelName(modelName) === PrimaryModelClass.modelName